Access to CF3-benzofulvenes via palladium-catalyzed cascade arylation/Trost–Oppolzer cyclization/double-bond isomerization

Abstract

Herein, we demonstrated a Pd-catalyzed cascade reaction that involves arylation, Trost–Oppolzer type Alder ene reaction, and double bond isomerization using the 4-(2-alkynylphenyl)-allylcarbonates and aryl boronic acids. This cascade process delivers a wide array of distinctive functionalized CF₃-benzofulvenes in good yields with high stereoselectivity (E). A single palladium catalyst orchestrates the two individual reactions in a single operation. Trost–Oppolzer type Alder ene reaction is the key in this transformation, also called a rare acid-free iso-Nazarov type cyclization.